Periodontosis is a widespread disease of the attachment apparatus of the teeth. Periodontopathies are caused by bacteria located in periodontal pockets (subgingivally). Some of these are bacteria which are bound adherently to the root surface and are usually Gram-positive and calcified to give concrements (subgingival calculus), and the others are bacteria which face the soft tissue of the pocket, are non-adherent and are usually Gram-negative, and which, for example, in part are motile in the pocket fluid. It is precisely these motile bacteria which play an essential role in the progression of periodontitis.
During the progression of periodontitis, the bacteria may migrate through the pocket's epithelium and penetrate into the subepithelial connective tissue, so that they surround the inflammatory infiltrate. Complicated interactions occur with the patient's immune defenses which are massively [lacuna] at this point and which lead, via (micronegroses, purulent abscesses or as reaction to the immune interaction for example through activation of osteoclastic endogenous cells, to loss of periodontal supporting tissue and development or deepening of a periodontal pocket and/or retraction of the gingival soft tissue. Particularly important in this connection are processes which take place deep inside the pocket or in problem regions such as, for example, the root furcation.
Recommended to date for reducing microbes in the pockets are mechanical cleaning techniques (for example scaling, curettages, cleaning with ultrasonic instruments) or simple pocket irrigations. Systemic administration of antibiotics is associated with considerable side effects, firstly because of the broad spectrum of the causative bacteria, and secondly because the bacteria are located outside the blood circulation. Local administration techniques through application of the antibiotics directly into the periodontal pockets often have an unreliable effect because diffusion into all the pocket regions is inadequate or deposition does not last long enough or the level of the active substance combination is inadequate. Antibiotics are therefore normally administered only as a measure supporting conventional, usually mechanical, procedures.
Because of the complex geometries of the affected periodontia or periodontal pockets, access to the diseased tissue regions is impeded, and the desired reduction in microbes is often not achieved. The consequence is after various time intervals, depending on the patient's immunological predisposition which is usually affected, recolonization of a previously treated pocket with a recurrence of the disease. It is particularly difficult to reduce microbes in the region of the infiltrated pocket epithelium and the adjoining connective tissue.
The first requirement for improved therapy is to have more detailed information about the current status of the disease to allow a better prediction to be made about the future development of the disease, especially the occurrence of acute episodes of the disease. It is to date possible to identify a previously active pocket only subsequently on the basis of pus discharge from the pocket. If this identification is possible, however, loss of supporting tissue has already occurred. Bacterial genetic testing which has recently been employed for the diagnosis of individual bacteria in periodontal pockets is costly and requires several days for evaluation. For these reasons, it is unsuitable for routine applications. It is moreover possible to derive information only about the genomes of the bacteria from such testing. Distinction according to the metabolic activities of the bacteria which cause periodontal disease is, however, impossible.
Examples of a periodontal procedure are evident from U.S. Pat. Nos. 5,422,093; 5,234,940; 5,211,938 and 5,079,262. These involve the identification and subsequent treatment of malignant and nonmalignant tissue abnormalities using aminolevulinic acid. This is used in the form of an aqueous active substance solution. Excitation of cell fluorescence in the violet region (375 nm to 440 nm) leads to a red fluorescence being observed. An observation filter is used to filter out the diffusely reflected blue-violet excitation light, and the metabolically active tissue region is seen red against a background which appears slightly greenish (intrinsic fluorescence of the healthy tissue).
The rate constant with which metabolism takes place in the cells makes it necessary for the active substance to remain over a prolonged time (at least 15 minutes, typically 120 minutes) essentially unchanged in contact with the tissue.